When was the last time you hopped, skipped or jumped? If it was back in the last century you wouldn't be alone - these are the movements that often vanish from our lives when we leave childhood and school sports behind.

Yet they're also the kind of high impact activities that grown up bones really thrive on - and they do a better job of boosting bone density than walking, according to exercise physiologist Dr Belinda Beck.

"Walking is great for your heart and blood vessels, but it's not brilliant for bone - unless you add some jumps into your walk. Even if you're running it's best to add jumps along the way for better bone density," says Beck, an associate professor with the School of Rehabilitation Sciences at Griffith University.

"Walking doesn't give the bones the stimulation they need to adapt and improve - bone cells need the 'loading' that comes with high impact exercise done quickly. Even running up and down stairs will load bone much better than just walking, but not as much as jumping."

Just how much jumping do bones need to keep them happy? The exact amount isn't clear because little research has been done on this, but around 40 jumps in the course of a workout, a walk or a run at least two or three times a week should help, she suggests - you could jump on and off a step, do some tuck jumps or just jump up and down on the spot.

"Jumping from side to side or backwards and forwards is better still - bone loves to be surprised. Skipping is good too and so is hopping on alternate legs," she says.

Other ways to give bones a healthy jolt include sports like volleyball, netball, basketball, tennis and squash as well as ballet and strength training. If you're a gym goer you'll find that some cardio classes include jump training too.

There's also plyometrics, a form of athletic training that's now appearing in some gyms and which involves rapid movements, jumping included, that help to build strength, speed and power. But although the terms plyometrics and jump training are ofen used interchangeably, they're not the same thing, Beck says.

"Plyometrics are good for bone indirectly because they build strength and power in muscles and stronger muscles can stimulate bone more. But there's no evidence that plyometric training is any better for bones than jumping. "

What's the advice if you've already developed osteoporosis, meaning you've already lost significant bone density and have a high risk of fracture? In that case, jumping is a double edged sword - it might have the potential to boost bones but it can also cause them to crack, which is why Beck recommendsagainst jumping for people with osteoporosis. Instead, strength training for the lower body is a better bet, along with balance training to reduce the risk of falls.

Not everyone with thinner bones has osteoporosis though - there's also osteopoenia, the middle ground that exists between normal bone density and osteoporosis, and that often develops in women around menopause. Is it safe to jump around with osteopoenia?

"If I were diagnosed with osteopoenia I'd be jumping, but then I'm not frail. If I were frail and had low bone density, I'd stick with strength training," says Beck." We don't know how much people with osteopoenia can do without hurting themselves, so to be on the safe side I'd recommend gentle jumps or perhaps simple foot stomps that don't jolt the spine, or jumping from side to side - but make sure you're not likely to fall and risk a broken hip. A safe option is jumping while you hold on to something like a railing or even a kitchen bench."